JP2017510929A - Graphene as a protective overcoat for magnetic media without the use of nucleation layers - Google Patents

Abstract

Graphene layers used as anticorrosive protective media for magnetic media overcome the existing problem of reducing the thickness of the carbon overcoat layer for magnetic media. Unlike amorphous carbon, which is commonly used as an anticorrosion layer, graphene impermeability to any known gaseous material is reduced by the lower magnetic field due to, for example, a graphene layer that may be as thin as a single layer of graphene. Enables complete corrosion protection of the medium. The graphene and the magnetic layer can be dry-transferred onto the magnetic recording disk so that the resulting interface is protected from contact with impurities.

Description

(Mutual reference with related applications)
This patent application claims the benefit of US Provisional Patent Application No. 61 / 976,240, filed April 7, 2014, the entire teachings of which are incorporated herein by reference.

  The demand for higher clock speeds in transistors and higher data storage density in magnetic recording disks leads to reduced device dimensions to overcome these limitations. A key to obtaining higher data storage density on magnetic recording disks is to minimize the distance between the magnetic read head and the magnetic medium. Conventionally, the space between the magnetic read head and the magnetic medium is covered with amorphous carbon as a corrosion-resistant material for protecting information stored in the magnetic medium.

According to one variant of the invention, the graphene layer used as a corrosion-resistant protective medium for magnetic media overcomes the existing problems associated with reducing the thickness of the carbon overcoat layer relative to the magnetic media. Unlike amorphous carbon, which is currently used as a corrosion resistant layer, graphene impermeability to any known gaseous material uses, for example, a graphene layer that can be as thin as a single graphene layer Thus, it is possible to completely protect the magnetic medium underneath. The dry transfer of graphene to a magnetic recording disk is enabled so that the obtained interface between the graphene and the magnetic layer does not come into contact with impurities.
According to one variant of the invention, the magnetic device comprises a magnetic substrate and a graphene transfer stack containing a thermal release tape and graphene. The surface of the graphene of the graphene transfer stack is in contact with at least one surface of (i) the magnetic substrate and (ii) an oxide film of the magnetic substrate.

  In further related variations, the graphene of the graphene transfer stack can include one and only one graphene layer, or can include multiple graphene layers. The surface of the thermal peeling tape may be in contact with the surface of the one and only graphene layer or the plurality of graphene layers. The graphene transfer stack can further comprise a polymer. The magnetic device can include, for example, a magnetic medium, and the magnetic substrate can include a magnetic layer of the magnetic medium, or the magnetic device can include a magnetic head, and the magnetic substrate can include the magnetic medium. A head magnetic transducer may be included. The oxidation coating may include a carbon thin film, such as diamond-like carbon. When the graphene transfer stack includes a polymer, the polymer can have tribological properties so that the polymer is suitable for use as a lubricating layer in the magnetic device. The polymer can comprise, for example, polyvinylidene fluoride-co-trifluoroethylene or poly (methyl methacrylate). The polymer can comprise a thickness between about 1 nm and about 2 μm.

According to another variant of the invention, a method of manufacturing a magnetic device is provided. The method comprises contacting the graphene surface of the graphene transfer stack with at least one surface of (i) a magnetic substrate and (ii) an oxide film of the magnetic substrate, wherein the graphene transfer stack is thermally exfoliated And removing the graphene of the graphene transfer stack from the thermal release tape to remove the graphene of the graphene transfer stack from (i) the magnetic substrate and (ii) the oxide film of the magnetic substrate. Transferring to at least one of the surfaces.
In a further related variation, the method transfers one and only one or more graphene layers to the surface of at least one of (i) the magnetic substrate and (ii) an oxide coating on the magnetic substrate. Including the step of The method can include the step of peeling the graphene of the graphene transfer stack from the thermal release tape by applying heat and pressure to the graphene transfer stack. The application of heat and pressure can include at least one of application of a roll-to-roll press to the graphene transfer stack and application of a hot press to the graphene transfer stack. The method further applies a thermal release tape to at least one of (i) the surface of the graphene on the metal substrate and (ii) the surface of at least one polymer layer covering the surface of the graphene on the metal substrate; and A step of forming the graphene transfer stack by peeling the graphene transfer stack from the metal substrate may be included. The graphene layer obtained as a result of transferring graphene from the graphene transfer stack to the surface of at least one of (i) the magnetic substrate and (ii) an oxide coating of the magnetic substrate has about 100 × 100 μm ² It can have an areal crack density of less than 5 defects.

The foregoing will become apparent from the following more detailed description of example embodiments of the invention as illustrated in the accompanying drawings. In the accompanying drawings, like reference numerals designate identical parts throughout the different views. The drawings are not necessarily drawn to scale, emphasis instead being placed upon illustrating embodiments of the invention.
FIG. 1 is a cross-sectional view of a typical magnetic hard disk medium according to the prior art, with a magnetic head floating above the top surface of the magnetic medium. FIG. 2 is a cross-sectional view of a magnetic medium with a graphene film as a protective overcoat according to one variation of the present invention. FIG. 3 is a process flow diagram for depositing graphene on a magnetic medium according to one variation of the present invention. FIG. 4A is a schematic process flow diagram for manufacturing a graphene transfer stack for single layer graphene and transferring the graphene to a target magnetic disk substrate according to one variation of the present invention. FIG. 4B is a schematic process flow diagram for manufacturing a graphene transfer stack for multilayer graphene and transferring the graphene to a target magnetic substrate according to one variation of the present invention. FIGS. 5A-5D are schematic layer structures of a graphene transfer stack according to one variation of the present invention, where FIG. 5A shows single layer graphene combined with thermal release tape, and FIG. And single layer graphene with thermal release tape, FIG. 5C shows multilayer graphene and thermal release tape, and FIG. 5D shows multilayer graphene with support polymer and thermal release tape. 6A and 6B are schematic layer structures of a graphene transfer stack applied to a magnetic substrate according to one variation of the present invention. FIG. 7 is a schematic process flow diagram according to a method for manufacturing a magnetic device according to one variation of the present invention. FIG. 8A is a plot of defect distribution within a single layer of graphene transferred onto a magnetic media substrate via thermal release tape technology, according to one variation of the present invention. FIG. 8B is a comparative bar graph plot of the corrosion density for a graphene transferred onto a CVD graphene versus magnetic substrate according to one variation of the present invention.

FIG. 1 is a cross-sectional view of a typical magnetic head disk medium (or magnetic disk) 100 with a magnetic head 101 floating on the top surface of the magnetic disk 100 according to the prior art. The magnetic disk 100 is used to record data through a signal output from the magnetic head 101, and the magnetic head includes a magnetic transducer 106. The magnetic disk 100 includes a substrate 102, which can be made of, for example, glass, aluminum, or an aluminum-magnesium alloy. The magnetic layer 103 of the disk 100 can be formed of, for example, a multilayer made of ferromagnetic metal such as cobalt deposited by sputtering. Above the magnetic layer 103 is a protective overcoat 104, typically a carbon film, for example Plasma-Enhanced Chemical Vapor Deposition (PECVD), sputtering, ion beam deposition. Deposited by (Ion Beam Deposition) (IBD) or other forms of thin film deposition. The protective overcoat 104 is conventionally less than about 2 nm thick. Finally, a thin layer of fluorine-based lubricant 105 (eg, less than 1 nm thick) is deposited, for example, via vapor deposition or dip-and-pull methods. The circular magnetic disk 100 rotates at a high speed, for example, at a speed exceeding 5,000 rpm. The magnetic head 101 is that it less than 10nm away from the surface of the magnetic disk 100, at a height indicated as H _F 1, to float the disc 100 up.
Electric corrosion tends to occur in the magnetic disk 100. This is due to moisture constituting the conductive electrode between the metal magnetic thin films of the magnetic layer 103. The carbon thin film of the protective overcoat 104 functions as a protective shield for the magnetic layer 103. Since the magnetic head 101 is very close to the magnetic disk 100, the magnetic head 101 will hit the magnetic disk 100 even with a slight movement of the hard disk drive in which the magnetic disk 100 is incorporated.

The carbon thin film of the protective overcoat 104 should be as thin as possible, so that the magnetic head 101 floats closer to the magnetic layer 103. By floating the magnetic head 101 closer to the surface of the magnetic disk 100, a higher areal density associated with the magnetic disk 100 can be obtained due to a decrease in the spacing of the magnetic heads.
One variation of the present invention allows for a reduction in the spacing of the magnetic heads while maintaining the corrosion resistance of the protective layer.
A description of illustrative aspects of the invention follows.
FIG. 2 is a cross-sectional view of a magnetic medium 200 with a graphene film as a protective overcoat 104 according to one variation of the present invention. In the variant of FIG. 2, as typically required for a conventional carbon protective overcoat 104 (see FIG. 1) or for a graphene overcoat grown directly on the magnetic substrate, A thin layer of graphene is used as the protective overcoat 204 without the need to apply a nucleation layer to the lower surface of the protective overcoat 204. As a result of the avoidance of the use of nucleation layers and thin graphene layers, the graphene protective overcoat 204 according to one variant according to the invention can be made thinner than the conventional amorphous carbon protective overcoat 104. . Similarly, the variation of FIG. 2 includes a substrate 202, a magnetic layer 203, and a lubricant film 205, which are formed, for example, by the prior art described above for the substrate 102, magnetic layer 103, and lubricant film 104 of FIG. obtain. The magnetic head 201, its incorporated magnetic transducer 206, and the magnetic head floating height _HF are also shown.

In general, the magnetic spacing for a magnetic medium can be calculated as follows:
T _C + T _L + H _F = M (Equation 1)
Here, T _C is the thickness of the carbon-made overcoat of the magnetic medium, T _L is the thickness of the lubricant film, H _F is the floating height of the magnetic head, and M is the magnetic medium Magnetic spacing.
From equation (1), if the equivalent of other points, minimizing the thickness T _C of the carbon steel overcoat of the magnetic media, result in a decrease of the magnetic gap M, also therefore higher on this hard It can be understood that it will produce areal density capacity. Thus, by providing a thinner protective overcoat 204, magnetic media 200 in accordance with the deformation of the Figure 2, by giving the thickness T _C of the carbon steel overcoat thinner magnetic media, having a higher surface density The thickness is that of the protective overcoat 204. The thinner protective overcoat 204 of FIG. 2 does not require a nucleation layer and can be as thin as the thickness of a single graphene layer, which is the thinnest associated with crystalline carbon It is a known form.

As described in more detail below, according to one variation of the present invention, a graphene film is transferred to a magnetic disk through a dry transfer method to form a protective overcoat 204. The dry transfer is simplified through the use of heat release tape. When the graphene is transferred to the magnetic media layer structure, there is no need for a catalyst layer for graphene growth. The thermal stripping tape with graphene on one side has a carbon film that does not have a carbon thin film nucleation layer or is simply a thin oxidation barrier and is extremely thin and cannot be an effective corrosion protection layer alone. Arranged on a magnetic medium. Heat and pressure facilitate peeling of the graphene layer from the heat release tape. In order to obtain better results, the surface of the magnetic medium can be plasma etched prior to application of the graphene layer to remove any oxide film. A very thin oxidation barrier layer of carbon film can be deposited on the surface of the magnetic media to prevent oxidation. The thickness of the carbon film should be sufficient, for example, to inhibit or retard the immediate oxidation process during manufacture, but not thick enough to prevent prolonged corrosion.
According to one variant of the invention, the graphene layer used as a corrosion-resistant protective medium overcomes the existing problem of reducing the thickness of the carbon overcoat layer. Unlike amorphous carbon, which is currently used as a corrosion resistant layer (e.g., the conventional protective overcoat 104 in FIG. 1), graphene impermeability to any known gaseous material is, for example, the ultimate thinnest carbon. A single layer of graphene representing the layer allows complete corrosion protection of the underlying magnetic medium. Graphene application usually requires either a wet transfer technique or direct growth on the graphene nucleation layer. However, these techniques are incompatible with magnetic memory disks because they increase the distance between the magnetic read head and the magnetic medium, such as when a nucleation layer is used. Or in the case of a metal-based nucleation layer, the magnetic information is screened; or if wet transfer technology is used, moisture and / or moisture is reduced so that the integrity of the magnetic layer is weakened. It is to be introduced into the magnetic disk.

The method according to one variant of the invention allows a dry transfer of the graphene to the magnetic recording disk so that the resulting interface between the graphene and the magnetic layer is protected from contact with impurities. And The graphene is embedded in the magnetic hard disk at a specific stage in the manufacturing process. An example is depicted in FIG.
FIG. 3 is a process flow diagram for depositing graphene on a magnetic medium according to one variation of the present invention. In step 310, a magnetic layer 203 (see FIG. 2) is deposited on the substrate 202. In step 311a, a thin oxide film, for example made of diamond-like carbon, is sufficient to prevent or weaken an immediate oxidation process, for example during manufacture, but not thick enough to prevent long-term corrosion The thickness can be deposited, for example, less than about 6 mm, or between about 0.1 and about 0.6 mm. In step 311b, any oxide film on the surface of the magnetic layer 203 can be removed using a plasma etching apparatus. In step 312, the graphene is placed on top of the magnetic medium using a heat release tape. In step 313, methods using heat and pressure, such as hot pressing, are used to transfer graphene from the thermal release tape to the magnetic media. In step 314, post processing of the magnetic media, such as lubrication, ultraviolet light, testing, and any other post processing is continued.
As used herein, a “graphene transfer stack” is a substance that contains at least graphene and is used to transfer graphene to the surface of a magnetic device, such as a magnetic medium, such as a magnetic hard disk Say the stack. The graphene transfer stack can include a thermal release tape. For example, the graphene transfer stack can be any of those shown in FIGS. 5A-5D, which are further discussed below.

FIG. 4A is a schematic process flow diagram for manufacturing a graphene transfer stack for single layer graphene and transferring the graphene to a target magnetic disk substrate according to one variation of the present invention. FIG. 4B is a schematic process flow diagram for manufacturing a graphene transfer stack for multilayer graphene and transferring the graphene to a target magnetic substrate according to one variation of the present invention.
The process flow diagrams of FIGS. 4A and 4B are examples of possible process flow diagrams that can be used to produce the graphene transfer stack shown in FIGS. 5A-5D, although other process flow diagrams can be used. It will be understood that there is. Briefly, in steps 420a / 420b of FIGS. 4A and 4B, graphene is grown on one or more surfaces of a metal substrate such as copper. In steps 421a / 421b of FIGS. 4A and 4B, a polymer can be applied on the graphene, and in steps 422a / 422b of FIGS. 4A and 4B, a thermal release tape is coated with the polymer by, for example, a bonding method. Applied above. In steps 423a / 423b of FIGS. 4A and 4B, the metal substrate is delaminated from the stack. In FIG. 4A, this results in the graphene transfer stack shown at 423a, which can include the coated polymer and thermal release tape on top of a single layer of graphene. This graphene transfer stack of 423a allows transfer to a single layer of graphene magnetic media, as shown in item 424a of FIG. 4A. Alternatively, as shown in FIG. 4B, a destacked stack 423b and a further graphene / metal substrate combination system 421b are combined to form a multi-stack 425b and a predetermined number of graphene layers are formed. By repeating the delamination process 423b and the multi-stacking process 425b, a graphene multilayer is formed on the transfer stack. Once in the final shape, the multilayered graphene is transferred to a magnetic medium as shown in item 424b of FIG. 4B.

5A-5D are schematic layer structures of a graphene transfer stack according to one variation of the present invention, where FIG. 5A shows single layer graphene 504a combined with thermal release tape 507a, and FIG. FIG. 5C shows multilayer graphene 504c and thermal release tape 507c with polymer 508b and thermal release tape 507b, and FIG.5D shows multilayer graphene with support polymer 508d and thermal release tape 507d. 504d is shown.
6A and 6B are schematic layer structures of a graphene transfer stack applied to a magnetic substrate according to one variation of the present invention. In FIG. 6A, the graphene transfer stack 609a includes a heat release tape 607a and a graphene 604a, and is in contact with the surface of the magnetic substrate 603a. In FIG. 6B, the graphene transfer stack 609b includes a heat release tape 607b and a graphene 604b, and is in contact with the oxide film 631 of the magnetic substrate 603b.
FIG. 7 is a schematic process flow diagram according to a method for manufacturing a magnetic device according to one variation of the present invention. In step 741, the method includes contacting the surface of the graphene of the graphene transfer stack with the surface of the magnetic substrate or the surface of the oxide film of the magnetic substrate. The graphene transfer stack includes a heat release tape and the graphene. In step 742, the method includes the steps of peeling the graphene of the graphene transfer stack from the thermal release tape and transferring the graphene of the graphene transfer stack to the surface of the magnetic substrate or the oxide film of the magnetic substrate. Including.
Further details of the steps involved in the method of manufacturing the graphene transfer stack, such as those shown in FIGS. 5A-5D, according to one variation of the present invention, include the following items (i) to (vii): )It is in:

(i) The optimal starting material is a metal substrate, where single layer graphene (SLG) is grown on at least one of the metal substrate surfaces, but other substrates and other types of graphene (e.g. It is also possible to use bilayer or multilayer graphene). A cleaning step can be performed to minimize contaminants on the SLG surface. These steps can include, but are not limited to, solvent cleaning, plasma treatment and thermal annealing.
(ii) Direct application of thermal release tape 507a to graphene 504a via a suitable application method (eg, laminating method) will result in a transfer stack, as depicted in FIG. 5A. Alternatively, deposition of a polymer layer on top of the SLG that will form the transfer stack can be utilized, resulting in the transfer stack of FIG. 5B. Includes bar coating or any other method that results in the deposition of a thin polymer layer 508b on the surface, such as spin coating, spray coating, polymer vapor deposition, Langmuir-Blodgett deposition or direct deposition from melt However, methods not limited to these can be used to complete the deposition of the polymer layer 508b on the transfer stack, such as that shown in FIG. 5B.

(iii) Application of the thermal release tape to the upper surface of copper foil, SLG and polymer stack, for example, by bonding. One example of a thermal release tape 507a that can be used in accordance with a variation of the present invention is REVALPHA tape sold by Nitto Denko Corporation of Osaka, Japan. It will be appreciated that other heat release tapes can be used. The polymer 508b forming the transfer stack of FIG. 5B may be selected such that it will contribute to the graphene transfer properties and characteristics. In one variation according to the present invention, the thin polymer layer 508b may constitute tribological properties such that the polymer is suitable for use as a lubricating layer in the magnetic device. At least a portion of the thin polymer layer 508b can be intended to remain with the graphene after being transferred to the magnetic substrate, so that the graphene is functionalized, for example, against wear by a magnetic read head. In one variation in accordance with the present invention, the polymer layer 508b comprises the copolymer polyvinylidene fluoride-co-trifluoroethylene (hereinafter P (referred to as VDF-TrFE) or poly (methyl methacrylate) (hereinafter referred to as PMMA). The thickness of polymer 508b is adjusted according to the optimum transfer properties, but usually has a thickness of more than 1 nm and less than 2 μm.
(iv) Delamination of the graphene transfer stack from the copper foil substrate (see 423a / 423b in FIGS. 4A and 4B). This step can be completed by methods such as, but not limited to, chemical removal of the copper or chemical delamination.
(v) A multilayer graphene transfer stack is produced as depicted in FIG. 4B. A method that allows a surface treatment and / or functionalization of the surface suitable to obtain the required properties allows for continuous delamination and enhancement of the multi-layering stages 423b / 425b.

  (vi) Application of the graphene transfer stack to the target substrate such as the magnetic layer 203 of FIG. The graphene transfer stack has a structure as depicted, for example, in FIGS. 5A-5D. The graphene transfer stack is applied under environmental conditions suitable for optimal release of the thermal release tape 507a-d. Application to the surface of the graphene transfer stack will usually be based on the application of pressure and / or heat. Other application methods, such as, but not limited to, electrostatic coupling, may be performed for optimal exfoliation of graphene layers 504a-d as well. Prior to application of the graphene transfer stack, the target surface may be treated by cleaning and / or plasma treatment to promote the attachment / bonding of graphene 504a-d to the magnetic disk surface, and the presence of contaminants. Can be minimized. The pressure helps to achieve a good bond between the graphene transfer stack and the target surface. The heat will also help to achieve a good connection between the graphene and the substrate, but this is also the mechanism for delamination of the transfer tape from the graphene or polymer film But it can be. After delamination of the graphene transfer stack, no residue from the tape should remain on the target surface. The graphene transfer stack can be applied by a technique such as a roll-to-roll method or a hot press method. For example, the hot pressing method can be performed at a temperature 5 ° C. higher than the peeling temperature of the tape control, and therefore when the tape peels at 120 ° C. or higher according to the tape specifications, The temperature should therefore be set at about 125 ° C. For example, the hot pressing method can utilize a pressure of about 10 MPa or less, typically around 5 MPa. In one example, the hot press technique taught in the following reference (1) can be used. The teachings of this reference are incorporated herein by reference in their entirety. In another example, the roll-to-roll technique taught in reference (2) below can be used. The teachings of this reference are incorporated herein by reference in their entirety.

(vii) Once the graphene is applied to the surface, a post-application modification step can be performed on either the polymer or the graphene layer. These can include, but are not limited to, electrical polarization or annealing. Such a method can help in improving the properties of the deposited structure or in improving the adhesion of additional layers on the top surface of the graphene.
When assembling a magnetic medium according to one variation of the present invention, oxidation to the magnetic layer can occur when the magnetic medium is removed from the sputtering apparatus. This can be overcome by removing the oxidation using a plasma etching apparatus. Alternatively, an extremely thin layer of carbon film is sufficient on the magnetic medium to protect against immediate oxidation, as discussed above in connection with FIG. On the other hand, it can be coated with a thickness that is not sufficient.
When the magnetic disk is coated with graphene according to a variation of the present invention, the graphene may completely cover or substantially completely cover the surface of the magnetic medium. As an example, FIG. 8A shows a defect in a single layer of graphene being transferred via a thermal release tape technique according to one variation of the present invention onto a round magnetic media substrate having a diameter of about 6.35 cm (2.5 in). (Ie, holes or cracks) is plotted. The results are shown as crack density per 100 × 100 μm ² on the y-axis versus crack area on the x-axis (μm ² ). Using visible optics techniques, the graphene coverage was determined to be 99.5% and the defect surface density was 3.8 cracks / holes per 100 × 100 μm ² . In one variation according to the invention, the graphene layer resulting from the transfer of graphene from the graphene transfer stack to (i) the magnetic substrate and (ii) at least one surface of the oxide film of the magnetic substrate is 100 × 100 μm ² It can have a crack surface density of less than about 5 defects (ie, holes or cracks) per hit.

FIG. 8B depicts the effectiveness of graphene with similar properties as a corrosion barrier. Industry standard corrosion tests were performed on standard samples of CVD graphene with similar performance (FIG. 8B, left) and graphene transferred on a magnetic substrate (FIG. 8B, right) according to one variation of the invention. Corrosion density (mm ² ) is indicated on the y-axis. These test results demonstrate that graphene transferred according to one variant of the present invention is a suitable anticorrosion layer for magnetic substrates in accordance with industry standards.
One variant according to the present invention offers the advantage of reducing the thickness of the carbon film of the magnetic medium, avoids the use of a nucleation layer that increases the magnetic spacing and can also result in corrosion to the magnetic medium as well. The use of chemicals to remove the nucleation layer with etching is avoided. Thus, one variant according to the invention makes it possible to achieve a higher areal density for each magnetic medium. Industrial applications include, for example, protective coatings on hard disk drive magnetic media or magnetic heads.
The term “graphene” as used herein is used to denote single layer graphene (SLG), bilayer graphene (BLG) and multilayer graphene (MLG).
The term “oxidation coating” as used herein is thick enough to prevent or attenuate the immediate oxidation process associated with the underlying substrate, eg, during manufacture, but the corrosion of the underlying substrate over time. Is used to describe a coating that is not thick enough to prevent, for example, less than about 6 mm, or having a thickness between about 0.1 and about 0.6 nm. For example, such oxide coatings can include very thin films of carbon, such as diamond-like carbon, such as carbon films having a thickness between about 0.1 and about 0.6 nm.

As used herein, a “thermal release tape” is a tape that is peeled from an underlying substrate, possibly when heat is applied in combination with pressure.
As used herein, “magnetic device” includes any type of magnetic medium as well as a magnetic head. For example, when the magnetic device is a magnetic medium, the medium can include a magnetic layer, for example, a layer 203 containing a ferromagnetic material, and the magnetic layer can be used as a recording medium in, for example, a hard disk. It will be understood that all types of magnetic media are intended to be included in the terms “magnetic device” and “magnetic medium”. In another example, the term “magnetic device” can refer to a magnetic head, which includes a magnetic transducer, such as a disk read and / or write head, and more particularly a hard disk read / write head. It is possible. It will be appreciated that all types of such devices, magnetic heads and magnetic transducers can be coated with graphene according to the techniques taught herein. The term “magnetic substrate” as used herein includes a portion of a magnetic device that is magnetic, ie, for example in a magnetic medium, the magnetic substrate can be a magnetic layer such as 203 in FIG. 2, while the magnetic device The magnetic substrate can be a magnetic transducer such as 206 in FIG.

References:
(1) U.S. Pat. No. 8,916,013 B2, entitled “Method for Transferring Graphene Using a Hot Press” by Hong et al.
(2) Hong et al., “Roll-to-roll Transfer Method of Graphene, Graphene Roll Produced by the Method, and Roll-to-roll Transfer Method for Graphene, US Pat. No. 8,916,057 B2, entitled “Graphene Roll Produced by the Method, and Roll-to-Roll Transfer Equipment for Graphene”.
The teachings of all patents, published applications and cited references are incorporated herein by reference in their entirety.

  While the invention has been illustrated and described with reference to illustrative embodiments thereof, those skilled in the art will recognize that various changes in form and detail may be made within the scope of the appended claims. It will be understood that this can be done in this embodiment without departing from the scope.

While the invention has been illustrated and described with reference to illustrative embodiments thereof, those skilled in the art will recognize that various changes in form and detail may be made within the scope of the appended claims. It will be understood that this can be done in this embodiment without departing from the scope.
Another aspect of the present invention is as follows.
[1] A magnetic device,
A magnetic substrate, and
A graphene transfer stack comprising thermal release tape and graphene,
Including
A magnetic device, wherein a surface of graphene of the graphene transfer stack is in contact with at least one surface of (i) the magnetic substrate and (ii) an oxide film of the magnetic substrate.
[2] The device according to [1], wherein the graphene of the graphene transfer stack includes only one and only one layer of graphene.
[3] The device according to [2], wherein the surface of the thermal peeling tape is in contact with the surface of only one and only one layer of the graphene.
[4] The device according to [2], wherein the graphene transfer stack further contains a polymer.
[5] The device according to [1], wherein the graphene of the graphene transfer stack includes a plurality of layers of graphene.
[6] The device according to [5], wherein the surface of the thermal peeling tape is in contact with one surface of the plurality of graphene layers.
[7] The device according to [5], wherein the graphene transfer stack further contains a polymer.
[8] The device according to [1], wherein the magnetic device includes a magnetic medium, and the magnetic substrate includes a magnetic layer of the magnetic medium.
[9] The device according to [1], wherein the magnetic device includes a magnetic head, and the magnetic substrate includes a magnetic transducer of the magnetic head.
[10] The device according to [1], wherein the oxide film includes a carbon thin film.
[11] The device according to [10], wherein the carbon thin film contains diamond-like carbon.
[12] The device according to [1], wherein the graphene transfer stack further contains a polymer.
[13] The device according to [12], wherein the polymer includes at least one of polyvinylidene fluoride-co-trifluoroethylene and poly (methyl methacrylate).
[14] The device according to [12], wherein the polymer has a thickness of between about 1 nm and about 2 μm.
[15] The device according to [12], wherein the polymer has tribological properties suitable for use as a lubricating layer in the magnetic device.
[16] A method of manufacturing a magnetic device, the method comprising:
Contacting the surface of the graphene of the graphene transfer stack with at least one surface of (i) the magnetic substrate and (ii) the oxide film of the magnetic substrate, wherein the graphene transfer stack comprises the thermal peeling tape and the A process comprising graphene, and
Peeling the graphene of the graphene transfer stack from the thermal release tape to remove the graphene of the graphene transfer stack from: (i) the magnetic substrate; and (ii) at least one of the oxide films of the magnetic substrate. Transferring to the surface,
Said method.
[17] The method according to [16], including a step of transferring only one layer of graphene and only one layer thereof to at least one of the surfaces of (i) the magnetic substrate and (ii) an oxide film of the magnetic substrate. Method.
[18] The method according to [16], comprising a step of transferring a plurality of layers of graphene to at least one of the surfaces of (i) the magnetic substrate and (ii) an oxide film of the magnetic substrate.
[19] The method according to [16] above, comprising the step of peeling the graphene of the graphene transfer stack from the thermal peeling tape by applying heat and pressure to the graphene transfer stack.
[20] The method according to [19], wherein the application of heat and pressure includes at least one of application of a roll-to-roll press to the graphene transfer stack and application of a hot press to the graphene transfer stack.
[21] Further, a thermal peeling tape is applied to at least one of (i) the surface of the graphene on the metal substrate and (ii) the surface of the at least one polymer layer on the surface of the graphene on the metal substrate. ,as well as
Delamination of the graphene transfer stack from the metal substrate;
The method according to [16] above, comprising the step of forming the graphene transfer stack.
[22] A graphene layer produced as a result of transferring graphene of the graphene transfer stack to at least one of the surfaces of (i) the magnetic substrate and (ii) an oxide film of the magnetic substrate is 100 × 100 μm 2 [16] The method according to [16] above, which has a crack surface density of less than about 5 defects.

Claims (22)

A magnetic device,
A magnetic substrate, and a graphene transfer stack comprising thermal release tape and graphene,
Including
A magnetic device, wherein a surface of graphene of the graphene transfer stack is in contact with at least one surface of (i) the magnetic substrate and (ii) an oxide film of the magnetic substrate.   The device of claim 1, wherein the graphene of the graphene transfer stack comprises only one and only one layer of graphene.   3. The device of claim 2, wherein the surface of the thermal release tape is in contact with the surface of only one and only one layer of graphene.   The device of claim 2, wherein the graphene transfer stack further comprises a polymer.   The device of claim 1, wherein the graphene of the graphene transfer stack comprises a plurality of layers of graphene.   6. The device according to claim 5, wherein a surface of the thermal peeling tape is in contact with a surface of one of the plurality of graphene layers.   6. The device of claim 5, wherein the graphene transfer stack further comprises a polymer.   The device of claim 1, wherein the magnetic device comprises a magnetic medium and the magnetic substrate comprises a magnetic layer of the magnetic medium.   The device of claim 1, wherein the magnetic device comprises a magnetic head and the magnetic substrate comprises a magnetic transducer of the magnetic head.   The device of claim 1, wherein the oxide film comprises a carbon thin film.   11. The device of claim 10, wherein the carbon thin film comprises diamond like carbon.   The device of claim 1, wherein the graphene transfer stack further comprises a polymer.   13. The device of claim 12, wherein the polymer comprises at least one of polyvinylidene fluoride-co-trifluoroethylene and poly (methyl methacrylate).   The device of claim 12, wherein the polymer has a thickness between about 1 nm and about 2 μm.   13. The device of claim 12, wherein the polymer has tribological properties suitable for use as a lubricating layer in the magnetic device. A method of manufacturing a magnetic device, the method comprising:
Contacting the surface of the graphene of the graphene transfer stack with at least one surface of (i) the magnetic substrate and (ii) the oxide film of the magnetic substrate, wherein the graphene transfer stack comprises the thermal peeling tape and the A step of containing graphene, and exfoliating the graphene of the graphene transfer stack from the thermal release tape to remove the graphene of the graphene transfer stack from (i) the magnetic substrate and (ii) the oxide film of the magnetic substrate. Transferring to at least one of the surfaces;
Said method.   17. The method of claim 16, comprising the step of transferring one layer of graphene and only the single layer thereof to at least one of the surfaces of (i) the magnetic substrate and (ii) an oxide film of the magnetic substrate.   17. The method of claim 16, comprising transferring a plurality of layers of graphene to at least one of the surfaces of (i) the magnetic substrate and (ii) an oxide film of the magnetic substrate.   17. The method of claim 16, comprising applying heat and pressure to the graphene transfer stack to exfoliate the graphene of the graphene transfer stack from the thermal release tape.   20. The method of claim 19, wherein the heat and pressure application comprises at least one of a roll-to-roll press application to the graphene transfer stack and a hot press application to the graphene transfer stack. And applying a thermal release tape to at least one of (i) the surface of the graphene on the metal substrate and (ii) the surface of at least one polymer layer on the surface of the graphene on the metal substrate, and Delamination of the graphene transfer stack from a metal substrate;
17. The method of claim 16, comprising forming the graphene transfer stack.   About 5 graphene layers per 100 × 100 μm 2 are formed as a result of transferring the graphene of the graphene transfer stack to at least one surface of (i) the magnetic substrate and (ii) an oxide film of the magnetic substrate. 17. The method of claim 16, having a crack surface density of less than defects.

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